Adding support for RenderSection

* Adding unit tests for DefineSection \ RenderSection
* Changes per code review feedback

src/Microsoft.AspNet.Mvc.Razor/Properties/Resources.Designer.cs

@@ -123,7 +123,7 @@ namespace Microsoft.AspNet.Mvc.Razor
         }
 
         /// <summary>
-        /// Section '{0}' is not defined
+        /// Section '{0}' is not defined.
         /// </summary>
         internal static string SectionNotDefined
         {
@@ -131,7 +131,7 @@ namespace Microsoft.AspNet.Mvc.Razor
         }
 
         /// <summary>
-        /// Section '{0}' is not defined
+        /// Section '{0}' is not defined.
         /// </summary>
         internal static string FormatSectionNotDefined(object p0)
         {

src/Microsoft.AspNet.Mvc.Razor/RazorView.cs

@@ -11,7 +11,7 @@ namespace Microsoft.AspNet.Mvc.Razor
 {
     public abstract class RazorView : IView
     {
-        public IViewComponentHelper Component 
+        public IViewComponentHelper Component
         {
             get { return Context == null ? null : Context.Component; }
         }
@@ -22,7 +22,7 @@ namespace Microsoft.AspNet.Mvc.Razor
 
         protected TextWriter Output { get; set; }
 
-        public IUrlHelper Url 
+        public IUrlHelper Url
         {
             get { return Context == null ? null : Context.Url; }
         }
@@ -95,15 +95,6 @@ namespace Microsoft.AspNet.Mvc.Razor
 
         public abstract Task ExecuteAsync();
 
-        public void DefineSection(string name, HelperResult action)
-        {
-            if (SectionWriters.ContainsKey(name))
-            {
-                throw new InvalidOperationException(Resources.FormatSectionAlreadyDefined(name));
-            }
-            SectionWriters[name] = action;
-        }
-
         public virtual void Write(object value)
         {
             WriteTo(Output, value);
@@ -259,15 +250,25 @@ namespace Microsoft.AspNet.Mvc.Razor
             return new HtmlString(BodyContent);
         }
 
-        public HelperResult RenderSection(string name)
+        public void DefineSection(string name, HelperResult action)
         {
-            return RenderSection(name, required: false);
+            if (SectionWriters.ContainsKey(name))
+            {
+                throw new InvalidOperationException(Resources.FormatSectionAlreadyDefined(name));
+            }
+            SectionWriters[name] = action;
         }
 
-        public HelperResult RenderSection(string name, bool required)
+        public HelperResult RenderSection([NotNull] string name)
+        {
+            return RenderSection(name, required: true);
+        }
+
+        public HelperResult RenderSection([NotNull] string name, bool required)
         {
             HelperResult action;
-            if (PreviousSectionWriters.TryGetValue(name, out action))
+            if (PreviousSectionWriters != null &&
+                PreviousSectionWriters.TryGetValue(name, out action))
             {
                 return action;
             }
@@ -283,4 +284,4 @@ namespace Microsoft.AspNet.Mvc.Razor
             }
         }
     }
-}
+}

src/Microsoft.AspNet.Mvc.Razor/Resources.resx

@@ -139,7 +139,7 @@
     <value>Section '{0}' is already defined.</value>
   </data>
   <data name="SectionNotDefined" xml:space="preserve">
-    <value>Section '{0}' is not defined</value>
+    <value>Section '{0}' is not defined.</value>
   </data>
   <data name="ViewEngine_PartialViewNotFound" xml:space="preserve">
     <value>The partial view '{0}' was not found. The following locations were searched:{1}</value>

test/Microsoft.AspNet.Mvc.Razor.Test/RazorViewTest.cs

@@ -0,0 +1,111 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.AspNet.Mvc.Rendering;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc.Razor.Test
+{
+    public class RazorViewTest
+    {
+        private const string LayoutPath = "~/Shared/_Layout.cshtml";
+
+        [Fact]
+        public async Task DefineSection_ThrowsIfSectionIsAlreadyDefined()
+        {
+            // Arrange
+            Exception ex = null;
+            var view = CreateView(v =>
+            {
+                v.DefineSection("foo", new HelperResult(action: null));
+
+                ex = Assert.Throws<InvalidOperationException>(
+                        () => v.DefineSection("foo", new HelperResult(action: null)));
+            });
+            var viewContext = CreateViewContext(layoutView: null);
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Equal("Section 'foo' is already defined.", ex.Message);
+        }
+
+        [Fact]
+        public async Task RenderSection_RendersSectionFromPreviousPage()
+        {
+            // Arrange
+            var expected = new HelperResult(action: null);
+            HelperResult actual = null;
+            var view = CreateView(v =>
+            {
+                v.DefineSection("bar", expected);
+                v.Layout = LayoutPath;
+            });
+            var layoutView = CreateView(v =>
+            {
+                actual = v.RenderSection("bar");
+            });
+            var viewContext = CreateViewContext(layoutView);
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Same(actual, expected);
+        }
+
+        [Fact]
+        public async Task RenderSection_ThrowsIfRequiredSectionIsNotFound()
+        {
+            // Arrange
+            var expected = new HelperResult(action: null);
+            Exception ex = null;
+            var view = CreateView(v =>
+            {
+                v.DefineSection("baz", expected);
+                v.Layout = LayoutPath;
+            });
+            var layoutView = CreateView(v =>
+            {
+                ex = Assert.Throws<InvalidOperationException>(
+                        () => v.RenderSection("bar"));
+            });
+            var viewContext = CreateViewContext(layoutView);
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Equal("Section 'bar' is not defined.", ex.Message);
+        }
+        
+        public static RazorView CreateView(Action<RazorView> executeAction)
+        {
+            var view = new Mock<RazorView> { CallBase = true };
+            if (executeAction != null)
+            {
+                view.Setup(v => v.ExecuteAsync())
+                    .Callback(() => executeAction(view.Object))
+                    .Returns(Task.FromResult(0));
+            }
+
+            return view.Object;
+        }
+
+        private static ViewContext CreateViewContext(IView layoutView)
+        {
+            var viewFactory = new Mock<IVirtualPathViewFactory>();
+            viewFactory.Setup(v => v.CreateInstance(LayoutPath))
+                       .Returns(layoutView);
+            var serviceProvider = new Mock<IServiceProvider>();
+            serviceProvider.Setup(f => f.GetService(typeof(IVirtualPathViewFactory)))
+                            .Returns(viewFactory.Object);
+            return new ViewContext(serviceProvider.Object, httpContext: null, viewEngineContext: null)
+            {
+                Writer = new StringWriter()
+            };
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.Razor.Test/project.json

@@ -1,9 +1,11 @@
 {
   "version" : "0.1-alpha-*",
   "dependencies": {
+    "Microsoft.AspNet.Abstractions": "0.1-alpha-*",
     "Microsoft.AspNet.FileSystems": "0.1-alpha-*",
     "Microsoft.AspNet.Razor": "0.1-alpha-*",
     "Microsoft.AspNet.Mvc.Razor" : "",
+    "Microsoft.AspNet.Mvc.Rendering" : "",
     "Microsoft.AspNet.Testing" : "0.1-alpha-*",
     "Xunit.KRunner": "0.1-alpha-*",
     "xunit.abstractions": "2.0.0-aspnet-*",